How Much Grout Do I Need for Backsplash? The Complete Guide

Installing a backsplash in your kitchen or bathroom can add visual interest and protect your walls from water damage and stains. An important consideration when installing a backsplash is how much grout you will need. Properly grouting your backsplash ensures it is sealed, secure, and aesthetically pleasing.

Calculating the right amount of grout for your backsplash project prevents you from running out mid-project or having excess leftover. With some simple measurements and calculations, you can determine the perfect quantity of grout for your unique backsplash design.

In this complete guide, we will cover everything you need to know to find out how much grout you need for your backsplash, including:

  • What is Grout and Why it’s Important for Backsplashes
  • Factors that Determine How Much Grout is Needed
  • Measuring Your Backsplash Area
  • Calculating Square Footage
  • Estimating Grout Amount Based on Tile Size
  • Allowing for Grout Joints and Waste
  • Purchasing and Preparing Grout
  • Tips for Grouting Your Backsplash
  • Frequently Asked Questions

Let’s get started!

What is Grout and Why it’s Important for Backsplashes

Before calculating how much grout you need, it’s helpful to understand what grout is and why it’s so important for backsplash installations.

Grout is a cement-based material that is used to fill the joints between tiles. It creates a water-resistant seal that prevents moisture from penetrating and damaging the substrate behind the tiles. Grout also binds the tiles together for a secure installation.

For backsplashes in particular, grout provides the following benefits:

  • Seals the joints between splashback tiles to protect the wall from spills and moisture.
  • Creates a finished look by cleanly filling the gaps between tiles for a uniform appearance.
  • Allows flexibility for the tile installation to expand and contract with temperature changes.
  • Holds tiles in place for a sturdy installation that won’t shift or become loose over time.
  • Resists mold and mildew thanks to its water-resistant properties.

Because grout plays such a crucial role in successful backsplash installation, it’s important to apply the right amount. Too little grout can lead to cracks, leaks, and other problems down the road.

Now that you understand why grout is so important, let’s look at how to calculate the right amount for your project.

Factors that Determine How Much Grout is Needed

The quantity of grout needed for a backsplash depends on several factors related to your unique installation:

Size of the Backsplash Area

The overall square footage of your backsplash will significantly influence how much grout is required. Larger backsplashes will need more grout than smaller ones.

Tile Size

Smaller tile sizes mean more grout lines to fill, increasing the amount of grout needed. Larger tiles have fewer grout lines and may require less grout.

Width of Grout Lines

The standard grout line for backsplashes is 1/8 inch. Wider grout lines, like 1/4 inch, will increase the amount of grout required.

Grout Joint Style

The amount of grout needed can vary based on the grout joint style. Diagonal patterns require more grout than basic straight joints.

Tile Texture and Shape

Tiles with textured faces or irregular shapes can require more grout to properly fill the joints.

Once you know the details of your backsplash tile project, you can use this information to estimate how much grout you will need. Next, we’ll look at how to measure your backsplash area.

Measuring Your Backsplash Area

To determine the square footage of your backsplash, you’ll need to carefully measure the area you are tiling. Here are the steps:

1. Measure Length and Height

Use a tape measure to measure the length and height of your backsplash area. Capture the maximum dimensions.

2. Calculate Total Square Footage

Multiply the length by the height to determine the estimated square footage. Be sure to calculate in feet, not inches.

Example: For a backsplash that is 9 feet long and 4 feet high, the calculation would be:

9 ft x 4 ft = 36 sq ft

Always round up to the nearest whole foot when calculating. It’s better to have slightly more grout than not enough.

3. Factor in Irregular Areas

If the backsplash has any irregular areas, take separate measurements and make additions to determine the total estimated square footage.

Now that you know the approximate size of your backsplash area, you can use that information to estimate how much grout you will need.

Calculating Square Footage for Grout

As a general rule of thumb, one 25-pound bag of grout will cover 80 to 100 square feet of backsplash when applied at the standard 1/8 inch thickness.

With the square footage amount you calculated, determine how many bags of grout you will likely need:

  • Under 80 sq ft – You will need 1 bag of grout
  • 80-160 sq ft – You will need 2 bags of grout
  • 160-240 sq ft – You will need 3 bags of grout

And so on, dividing your total square footage by the 80-100 sq ft coverage per bag to find out approximately how many bags to purchase. Buying grout by the bag is more cost-effective than boxes or tubes.

You can cross-check your estimate using tile size as well, covered next.

Estimating Grout Amount Based on Tile Size

Another way to estimate the amount of grout needed is to consider your backsplash tile size. Here are some averages:

  • For mosaic tiles 1” or smaller, you will need 0.5-1 lb of grout per square foot.
  • For standard tiles 2”-4” in size, you will need 0.75-1 lb per square foot.
  • For large format tiles 6” or bigger, you will need 0.5 lbs per square foot.

Multiply your total backsplash square footage by the estimated lbs per square foot for your tile size.


  • 30 sq ft backsplash
  • Using 2” tiles
  • 0.75-1 lb per sq ft for standard 2” tiles
  • 30 sq ft x 1 lb per sq ft = 30 lbs of grout needed

Compare your estimates based on tile size and overall area. Purchase grout based on the higher estimate to ensure you have enough.

Don’t forget to account for extra grout needed for the joints and waste.

Allowing for Grout Joints and Waste

When estimating your grout needs, add a little extra to account for:

  • Grout joints – The gaps between the tiles require more grout than just the surface area alone. Add 5-10% more for grout joints.
  • Waste – It’s inevitable that you’ll have some leftover grout after finishing the job. Add 5-10% more grout to your estimate to accommodate waste.

It’s better to slightly overestimate and have leftover grout than to run out before the backsplash is fully grouted. Those extras can also come in handy for grout touch-ups down the road.

Purchasing and Preparing Grout

Once you’ve estimated how much grout you need for your backsplash, it’s time to purchase it and get it ready to use. Here are some tips:

  • Buy grout a few days in advance – That allows time to prepare and test it before grouting day.
  • Choose sanded or unsanded grout – Sanded grout is best for joints 1/8” or wider. Unsanded works for smaller grout lines.
  • Get color samples – Test grout colors on spare tiles to ensure it’s the right shade for your backsplash.
  • Read the packaging – Follow any mixing instructions and prep guidelines from the manufacturer.
  • Mix small batches – Only mix up enough grout to use within 30 minutes to prevent it from drying out.

Proper mixing and advance preparation helps ensure the grouting process goes smoothly.

Tips for Grouting Your Backsplash

Once you have the right amount of grout purchased and prepared, follow these tips for grouting success:

  • Work in small sections – Grout in 4-5 square feet at a time before moving to the next area.
  • Apply grout with firm pressure – Fill the joints fully, leaving no gaps or voids.
  • Work at consistent depth – Holding the grout float at the same angle helps keep lines even.
  • Clean tiles thoroughly – Wipe diagonally across tiles to remove excess grout.
  • Avoid dragging grout out of joints – Careful cleaning preserves filled joints.
  • Allow proper cure time – Don’t polish or seal grout until it has cured per manufacturer instructions.

With the right amount of grout and proper technique, you can achieve a flawless backsplash finish!

Frequently Asked Questions

Still have questions about calculating how much grout you need for backsplashes? Here are answers to some common questions:

How do I measure my backsplash area to find square footage?

Carefully measure the length and height of the backsplash space. Multiply length x height to get the square footage. Include any irregular areas. Round up when estimating.

What size grout lines should I use on my backsplash?

1/8 inch is the standard grout line width for backsplashes. Only go wider if specifically recommended for the type or size of tile you are installing.

Should I use sanded or unsanded grout for my backsplash?

Use sanded grout for joints 1/8 inch or larger. Stick to unsanded grout for thin grout lines less than 1/8 inch.

How can I tell if I’m applying the grout correctly and uniformly?

Ensure grout lines maintain consistent thickness by holding the float at the same angle across all tiles during application.

Can I use leftover grout from my backsplash for another project?

Only use leftover grout if it was never mixed with water. Discard any grout that was hydrated for your backsplash.

What’s the easiest way to calculate how much grout I need?

Divide your total backsplash square footage by 80-100 to estimate bags needed. Also calculate lbs needed based on your tile size. Take the higher estimate.


Determining the right amount of grout for your backsplash tiling project doesn’t need to be a guessing game with this comprehensive guide.

By carefully measuring your backsplash area, understanding key factors like tile size and joint width, and doing a few simple calculations, you can estimate the ideal quantity of grout to purchase. Allowing for extra grout needed for joints and waste helps guarantee you won’t run short.

With the right amount of quality grout and proper application, you can achieve a spectacular backsplash that protects your wall and looks amazing. Just be sure to leave the grout mixing and mess to us – your backsplash deserves an expert touch!